1. Field of the Invention
The present invention relates to a photocatalytic reactor with a light guide plate, in which the light guide plate can be rotated for guiding the propagation of an incident light so as to enhance the photocatalysis efficiency of the photocatalytic reactor.
2. The Prior Arts
In recent years, carbon dioxide emission has been increasing that makes the greenhouse effect more serious. To effectively improve this problem, many experts did many studies on how to use titanium dioxide (TiO2), silicon carbide (SiC), and gallium phosphide (GaP) to convert carbon dioxide by photocatalysis into formaldehyde (HCHO) and methanol (CH3OH). In the photocatalytic reduction reaction, the photocatalyst particles are uniformly mixed in a reactant solution to enhance the photocatalysis efficiency. Although such a way has a merit of increasing the photocatalysis efficiency, it is difficult to recover the photocatalyst from the reactant solution. And the treatment time of cost is relatively high. Additionally, another issue is how to increase exposure area of the photocatalyst to efficiently activate the photocatalysis. According to prior experimental results, TiO2 has a low light transmittance. Ultraviolet light can penetrate through TiO2 solution only 1 to 2 centimeter. Therefore, the photocatalysis of the deeper portion of TiO2 solution can not be activated. In 1977, an optical fiber photocatalytic reactor has been proposed, in which the optical fiber is coated with TiO2 on a surface thereof. A reactant is guided to contact with TiO2 film, and a light beam is coupled into and propagates inside the optical fiber; thereby activating the photocatalytic reduction reaction with carbon dioxide. For example, U.S. Pat. Nos. 5,875,384, 5,919,422, and 6,238,630 disclosed a light guide photocatalytic reactor, respectively. These patents employed an LED or other light sources as a reaction light source to activate the photocatalysis; thereby having a small reaction cavity and good photocatalysis efficiency. However, the photocatalytic reactor should be installed inside the reaction cavity. Thus, the mass transfer efficiency of the reactant is relatively lower.
For another examples, U.S. Pat. Nos. 5,480,524, 5,308,458, and 5,689,798 disclosed a rotatable reactor, respectively, which can increase the mass transfer efficiency and the photocatalysis efficiency of the reactant by a centrifugal force. Since the light source is disposed outside the reactor, if the reactant has a low light transmittance, that will reduce the photocatalysis efficiency.
Thus, it is desired to provide a new photocatalytic reactor that can overcome the above shortcomings.